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About OlDatZMan

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  • Location
    WA on island near water
  • Cars
    720 4x4, Metros, Leaf, GMC, VWs, the rest exceeds available space
  • Interests
    Too many
  • Occupation
    Half retired, sheet metal recently

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  1. Time Left: 12 days and 14 hours

    • FOR SALE
    • USED

    One bad cyl, Z24 engine, body fair, 5 spd, 4wd, I gave up on it, need it gone and don't want it to go to the crusher, pics on request, best offer over junk price, needs to be trailered.


    Clinton, Washington - US

  2. OlDatZMan

    720 Part # Thread

    I had to replace my pwr steering idler bearing and finding a x-ref from OEM was hard. Eventually found this: OD 3.1875”, ID 0.46875” Bearing: NTN 6203LUX8 NTN 6203LUX8 replacement is the 6203LLB NTN search NTN# via main page search, then on the next page search by competitor part number, listing 3: Note the different max rpm of bearings of the same size--the idler spins faster than crank speed 6203ZZ, 6203LLB, and 6203LLU, all the same dimensions and load capacities 6203ZZ is no seal, double shielded 6203LLB is double sealed nitrile rubber, non-contact type seal, 180000rpm 6203LLU is contact type seal nitrile rubber, 12,000 rpm
  3. OlDatZMan

    Boink boink

    OK Folks I’ve thought about this a lot and it’s time to cut my losses. The truck is worth fixing but the work involved would stretch my capabilities not to mention insult my comfort at my age so I’ve posted it in Classifieds. If I was 10 or 15 years younger, or this was 2WD I’d push on, but I’m not and it isn’t. So it goes. History of the truck is in the thread above which is more info than you’d get in from a craigslist seller. Head and intake/carb are on the engine but exh manifold and exhaust needs bolted on. One cylinder is low and needs honed and rings but the other cyls are good so I don’t see any reason why it could not be driven 30 or more miles to a new home, preferably to someone who values Nissans. Sale post is in classifieds along with a list of 240/60/80Z parts plus a J15 and transmission I have had sitting in my shop too long. Truck is going to be inexpensive from prices I’ve seen. Any other questions I’ll answer from Classifieds. I’ve gotten a lot of good advice and encouragement here which puts Ratsun on a high pedestal as a Datsun/Nissan resource. I’ve learned a lot. Many thanks to you all. I’m not done with Nissan, I have a diesel 720 to start on next. If this doesn’t sell it will just drop about 6 places down my priority list. If this post or parts of it are inappropriate here please advise and I’ll edit.
  4. OlDatZMan

    Boink boink

    Well like I said, I have done hone and rings once before, but the difference is then it was a RWD Zcar more like Mike's slant six (great engine), but now its a 4WD. The difference is that big lump under the pan. Yes I had thought about laying some impermeable film down over the crank---saran wrap, tarp, visquine, anything to help, maybe two layers, followed by a washdown after honing. One other thing I thought of that might help someone else is to wipe down parts within reach of ricocheting cutting particles with chainsaw bar oil, or maybe K&N air filter oil, the really sticky stuff, though I don't have any KN, which might help catch and hold particles so they don't bounce where you can't see them. And I've seen mention of slitting a large hose or somesuch to put 'round the crank journal. But with the pumpkin right there the question is the amount of access. I have had jobs where I finished saying "Damn I never want to do that again". One of which was a single lower intake manifold bolt on an 88 Isuzu Trooper 2.6 that I could not see and barely reach and took two hours to get off. And to add insult Isuzu made sure that in addition to the head cooling design flaw they built into the 2.6, that there was only one count one engine which would fit the trans on that otherwise sound vehicle: the trusty 2.6. It taught me that I never wanted to have anything to do with that engine ever again. You go through those things and you say never again. Which is what I'm trying to avoid now. So far I've rationalized this as a learning experience, but at some point there's the possibility it becomes self flagellation. The Trooper tried to deal with the pan issue by making the pan a two piece with the upper section cast aluminum with the lower sump having a bolt-on flange just like the 720 pan bolts to the block. That doesn't solve the problem of the oil pickup coming but it does give a better shot at being able to reach the pickup to unbolt it. I still have the Isuz pan and it would be nice if it would just bolt up, but of course no. Though I will dig it out and see if the z24 pan could be flanged to fit the Isuzu lower pan. BTW I always like the idea of a Cressida, the same way I like the Maxima diesel, but never had one or even was close to one.
  5. OlDatZMan

    Boink boink

    Simple question: Has anyone honed cylinders and installed new rings in a Z24 4wd 720 with the engine in the truck?
  6. OlDatZMan

    Boink boink

    Yeah Charlie you're right. It also immediately raises the question of whether to pull the engine which is another expansion of shop area needed, and more to put back together. I was trying to convince myself that since the other cylinders are ok now I would try to do #2 only, and that it might be possible to do it while the engine is in the truck. I have little interest in rebuilding the entire engine for cost or time needed; the truck is barely worth it, it will only be a local truck for me, and since I have another PU my truck need is not that pressing. Where do you stop when the engine is out? And if the engine is out, why not just find another block? I was just about to search for whether anyone has done rings in frame or a 720 4wd to see if that is even possible. I think it is, but not easy, though easier than pulling the engine. I re-ringed my 240Z but it had no front differential, and that was a tad over 40 years ago.
  7. OlDatZMan

    Boink boink

    Not much of an update. A week ago I bolted on and torqued the supposedly fresh head with 4 new intake valves and 4 old lapped exh valves using yet another new head gasket, and the EZ LOK repaired rocker bolt hole. After getting the cam timing wrong and making a couple other mistakes I was too embarrassed to publicly admit at the time, I corrected the cam timing to the point of being able to do a compression check. Compression on the formerly good cylinders was unchanged. Compression on the formerly low #2 cylinder was low and unchanged, an unwelcomed surprise that whacked my confidence. That suggested bad #2 rings. After a few days of mental recovery I rigged my compression tester to be able to inject air into #2, but not cobbled together as a full blown leakdown tester to check % leakage. I'm looking for location of the leak route, not the fact there is one. I fastened/ taped thin plastic wrap about 0.0005 thick over the crankcase vent, over the carb, and over the #2 exhaust port to try to show any flow out of 2 through valves or crankcase. Rotated crank so both #2 valves are closed. When injecting air with enough flow to hear flow, but not enough to force pistons to turn the crank, I can hear air flow in excess of what I would hope for a tight cylinder, but there’s no sign of flow out anywhere. Movement of plastic film may not be sensitive enough to be visible with low flow, and the carb cover admittedly cover has more leaks to reduce outflow if the intake valve is leaking. Can’t find my stethoscope (though I did find my missing Metro head I’d been looking for for two weeks), but I could not use the steth to move around to listen for air exit routes while I'm controlling airflow in at the same time. Will search more for the stethoscope but must wait til I get help to listen at probable leak locations, and then at improbable ones. Edit/add: Found stethoscope, rigged to a listening tube, air flow quickly located coming from cam chain hole. (Valve cover is off.) Yeah I should have thought about other possible crankcase venting exits other than CC ports, ie breather....the vertical cam chain cavity is a big one though nt a port. Bad #2 rings.
  8. OlDatZMan

    Boink boink

    No answer yet to my question so I'll rephrase: Shouldn't I be able to clearly sense compression on each cylinder when turning over the crank on this Z24 using a 1/2 ratchet even if the ratchet action isn't very fast? I know I certainly can feel compression when hand cranking my 51 Farmall Super A and it's only a 113CID 4 cylinder with 6:1 compression. I'll try just turning the crank pulley by hand which will make it easier to feel resistance. Just answered my own question: I can't turn the engine over by hand gripping the crank pulley. So I guess it does have compression and it's time to assemble a few more things to do a starter spin. Also knit together the exhaust system back together.
  9. OlDatZMan

    Boink boink

    That's the mistake I made last week. I left out some things this post; didn't want it to be too long. Rockers but 4 only the #1 valve lash is set. ******* Edit/add: I can't say that I have zero compression. I'm turning it over with a 1/2" ratchet on the crank which admittedly is not fast, but there doesn't seem to be much resistance, even thinking about a 5hp mower motor. I set the valves on the other 3 cylinders just now so all 4 should be talking to me especially since before all this recent work I had over 170 on a compression test (6 revolutions using the starter) on 1, 2, and 4. I haven't spun it with the starter yet but I guess that's the next try, but wanted to get some good news before I started reassembling all the things that came off changing the head gasket. Intake manifold is on but not exhaust. Cam sprocket bolt is snug but not torqued in case I needed to pull it again to change the valve timing which doesn't seem likely now.
  10. OlDatZMan

    Boink boink

    7-11-18, last three days: EZ LOK threaded insert installed to repair pulled threads on the intake side at the center rocker mount boss with the oil port. Head back on with new gasket and cam sprocket back on. Crank turns easily, no obstructions. @ crank mark TDC, #1 and #4 pistons at TDC line on cam boss just to right of rocker post casting line #1 valve lobes at 4:00 & 8:00 distributor rotor at ~ 7:00 from driver’s fender, ie pointing to #1 intake plug distributor wire No compression on #1 either with finger in the hole or spark plug snugged--haven't checked other cylinders and don't see the need to if #1 doesn't work. Crank pulley and distributor have not been removed since it last ran, reasonably well with one cylinder at 118 for compression If I r otate the crank to where distributor rotor is pointed at 9 and 4 the crank pulley, crank TDC mark is about 45 degrees BTDC I don’t see how the chain could have jumped at all, certainly not 45 degrees. Chain is US made, probably replaced (before I got the truck) when the last head gasket went on and the head was milled flat, I think less than 40k mile ago. Distributor timing is a different issue than cam timing and compression. Distributor could have been previously pulled and put back in wrong but I should still have compression turning the crank, and the truck DID run reasonably well before I pulled the head. I've marked out the valve durations on a paper degree wheel and turned the crank while referencing the wheel and all seems correct. How can I not have compression?
  11. OlDatZMan

    Boink boink

    Forum slow today. Condolences to admins trying to troubleshoot. This reply didn't take, trying again: RE using a longer bolt to reach remaining good threads in head: Hole depth in head: 1 3/8" (maybe not threaded to the bottom) Minus 1.4" locate bush stickout = 1 1/8" max hole depth Bolt length: 3" from cap face Upper cam bearing block height to cap screw surface: 2.250" 3" - 2.250 = 3/4" bolt threads max available, also meaning all hole threads at max bolt depth are failed 1 3/8 hole depth + 2.250 upper cam block = 3 5/8" max depth for new bolt (if hole threaded to bottom) 1 1/8" max hole depth - 3/4" OEM bolt engagement = 3/8" untouched threads at bottom of hole if the hole was threaded all the way to the bottom IF hole threaded all the way to the bottom, 3/8" might be enough for steel threads, but I don't think aluminum. And I doubt the hole is threaded to the bottom. Doesn't look very promising.
  12. OlDatZMan

    Boink boink

    I haven't measured the hole depth yet (I will now) but know the bolt went into the threads quite a ways, 6 or 8 turns. The OEM bolt is also long, 3". Finding a longer one would be harder than going to the local hardware store. Keeping the alignment bush means a new bush with an ID larger than the insert OD, meaning an even bigger hole and less material remaining for the insert. Also means finding a bigger bush and drilling the lower cam bearing block to match. One might possibly find a bush about the dia of the insert, chamfer the inside of one end, slice it down to a ring maybe 1/16" tall, chamfer the outside bottom of the OEM locate bush, and cut down its length so the internal and external chamfers f the two bush's engaged like a compression fitting. That's a lot of ifs, and grinding down a bush into a ring doesn't sound safe or fun. I don't have a reasonable solution yet. Just about anything is repairable, but there comes a time when someone not consumed by the repair just says "get another head'. Not there yet but the thought is closer than it used to be.
  13. I probably read Yeager's book 10 times. It's a great read about someone who could fly the pants off of anything he got into. Yes, he wouldn't quit, but he also had a number of traits including great eyesight, a feel for the air and the plane, and an unusual ability to grok mechanical systems that others didn't have. But I quit re-reading him when he ridiculed the Voyager flight. Dick Rutan probably was not Yeager class, but the Voyager book's description of the Voyager's flying qualities combined with the days involved and weather made that a huge achievement. The best other flying books I know are Saburo Sakai's (Martin Caidin) book Samurai, and the copter book Chicken Hawk by Robert Mason. I met Sakai once, at a fly-in in eastern WA. Watchign the long line of people in the hand-shaking line, I don't think many if any knew who Sakai was. That said, all air combat books need to be gauged relative to The Blond Knight of Germany, about Eric Hartmann.
  14. Followup from Chesterton: "When calculating torque or referencing torque values from a chart it’s not uncommon that the default value being used of a dry nut factor is .2. This value .2 is based on using new clean hardware bolts/studs & nuts. The 725 Anti-Seize uses a .18 k factor for the dry nut factor. You can either re-calculated the torque value using the .18 factor or just reduce the torque value by 10%. The best benefit about using anti-seizes with lower k nut factors that it helps you achieve the required load at a lower torque. Which in turn speeds up/shortens the installation time of the application. " Another benefit is adding some lubrication other than oil to reduce stiction. I want bolts to stay in and tight, but l also want multiple torqued bolts on a single assembly to have equal torque, and varying stiction can cause a wider variation of torques. Using a smidge of AS on my rocker bolt threads and under the cap head might have prevented the pulled out threads I'm dealing with now. Nice to know about iodine but I can't think of a bolt I'd never want to remove.
  15. OlDatZMan

    Boink boink

    Thanks Charlie and Crash. For the present I'm pushing on to see whether I'm headed for a reasonable repair time and cost, or down a rabbit hole. It's nice to see there are more choices than Heli. For any insert option I would need to remove the rocker bolt hole cam bearing locate bushing which would delete the locating benefit Nissan thought it needed. Is that acceptable? I don't see an easy or even reasonable way to install an insert and retain the locate bush. There's not much room on the top of the cam block mount tower. Drilling out for a threaded insert reduces the material needed to anchor an insert. Concern about insert purchase took me here (a Helicoil pdf): https://media.boellhoff.com/files/pdf1/helicoil-tangfree-en-0150.pdf There the relevant term is "residual wall thickness", the amount of material remaining after the original bolt bore is drilled out to the spec'd insert OD, found on pages 13, 17, and 18. For Heli: residual wall thickness = 0.375 x OD of insert M8-1.25 Helicoil OD is 9.62mm or 0.3787” Residual wall thickness for M8 Heli is 0.375 x 0.3787 = 0.142” 0.142” x 2 (walls) = 0.284” Total residual wall thickness of 0.284” plus M8 Heli OD of 0.3787” = 0.407" The locate bush is not centered on the cam block mount tower. My measured distance between aft oil feed bore and fwd cam block tower edge is 0.626”, which is sufficient. My measured minimum distance is between the locate bush OD and cam mount tower is 0.090” Therefore the residual wall thickness (at least for Helicoil) is less than stated minimum in the bore arc closest to the cam. I'd prefer EZ Lok for cost and simplicity but EZ LOK’s web site is a hassle--lots of scrolling and numerous pages without finding a residual wall thickness for their insert. EZ could learn something from the pdf above. But there is a distributor about 10 miles from me. This repair would be much be less time and hassle if done with the head on the block where it is now, rather than pulling off the head and then supporting it precisely on a 10" dia drill press table. What are your opinions about drilling with a hand drill with head installed vs pulling the head off and eating the time for that and another head gasket to drill out for the insert? The bolt is long so the drill angle would have to be fairly exact.
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